Myasthenia gravis 2

5. Pathophysiology
 In normal people, if there is a nerve impulse reaches the neuromuscular connection, the membrane depolarization aksonterminal presinaps experience that acetylcholine is released in a gap sinaps.Asetilkolin diffuses through the synaptic cleft and join membranpostsinaps acetylcholine receptors. This merger led to changes in permeability to sodium and potassium suddenly causing depolarization of the end plate known as an end plate potential (EPP).If the EPP is reaching the threshold will form an action potential in the muscle membrane that is unrelated to the nerve, which will be distributed throughout sarkolema. This action potential triggers a series of reactions resulting in the contraction of muscle fibers. After neuromuscular transmission occurs through relationships, astilkolin will be destroyed by the enzyme acetylcholinesterase.In myasthenia gravis, impaired neuromuscular conduction. Abnormalities in miasteniagravis disease occurs in motor endplate and not on membrane presinaps. Postsinaptiknya membranes damaged by immunological reactions. Because of the damage that the distance between the membrane and postsinaps presinaps be great so that more acetylcholine in the journey toward the motor endplate can be solved by cholinesterase. In addition, the number of acetylcholine that can be accommodated by the folds of the motor end plate postsinaps membrane becomes smaller. Because of these two factors is the contraction of the muscles can not last long.Abnormalities of the thymus gland in myasthenia gravis occurs. Although radiological abnormalities not visible because it is too small, but the thymus gland histological abnormalities in most pasienmenunjukkan. Young women tend to suffer from hyperplasia of the thymus, while the older man with thymic neoplasms. Electromyography showed decreased motor unit potential amplitude when the muscles are used constantly. Proof etiology auto-imunologiknya given by the fact that the thymus gland has a close relationship.In 80% of patients with myasthenia found an abnormal thymus gland. Approximately 10% of them showed structures thymoma and other sufferers are infiltratlimfositer germinativa thymus gland in the center without changes in other limfoster network.
6. Clinical ManifestationsMyasthenia gravis is thought to be an autoimmune disorder that damages the function of acetylcholine receptors and reduces the efficiency of the neuromuscular connection. Inisering state manifests as progressive disease that develops slowly. But the disease can remain localized to a particular muscle group.The clinical features of myasthenia gravis is very clear, from mild to local weakness in the whole body of a fatal weakness. Approximately 33% are only symptoms of ocular disorders with weakness of other muscles. Extremity weakness without ocular abnormalities jarangditemukan symptoms and there are approximately 20% of patients found to have difficulty chewing and swallowing. In 90% of patients, the initial symptoms such as ocular muscle disorders that cause ptosis and diplopia. At arise with unilateral or bilateral ptosis. After a few weeks to months, ptosis can be equipped with diplopia (ocular paralysis). Paralysis-bulbar paralysis that arise every day in the afternoon or evening. In the morning the pain was not bothered by any paralysis. But over time the bulbar paralysis may rise too early in the day so it may be said of the day the pain is not free from difficulty seeing.On examination can be found unilateral or bilateral ptosis, one paretik ocular muscles, paresis N III interna (pupil reaction). Diagnosis can be established by taking into account palpebral levator muscles of the eyelids.Although clearly palpebral levator muscle paralysis in myasthenia gravis, but sometimes still bisabergerak normal. But in the later stages of ocular muscle paralysis both sides will complete ptosis myasthenia gravis. If the disease is limited to the muscles of the eye, the way the disease is very mild and will not cause death.Myasthenia gravis also attacked the muscles of the face, larynx, and pharynx. On examination can be found paresis N VII are bilateral or unilateral LMN, chewing muscle weakness, paresis palate mole, faringeus arch, uvula, farings muscles and tongue. This situation can lead to regurgitation through the nose if the patient tries to swallow, abnormal noise, or a nasal voice, and the patient was not able to close the mouth, called a sign hanging jaw.Non-bulbar muscle weakness commonly found in the advanced stage of all. The first terkenaa dalah neck muscles, so that the head should be enforced by hand. Then the following anggotagerak muscles intercostal muscles. Mild muscle atrophy can be found at the beginning, but then it was not much worse again.Terserangnya respiratory muscles seen from a weak cough, and dyspnea attacks can eventually form and the patient no longer able to clean up lendir.Biasanya myasthenia gravis symptoms can be relieved by rest and with memberikanobat Anticholinesterase.
The symptoms may be more or experiencing exacerbations accordingly:1. Changes in hormonal balance, for example during pregnancy, fluctuations during the menstrual cycle ataugangguan thyroid function.2. The presence of comorbidities, especially upper respiratory tract infections and infections with diarrhea and fever.3. Emotional disturbances, most patients experience muscle weakness when they are in a state of tension.4. Alcohol, especially when mixed with soda water containing quinine, a drug yangmempermudah occurrence of muscle weakness, and other drugs
7. DiagnosisDiagnosis can ditegakkkan based on history and physical examination. It is important to know the true state of myasthenia gravis. Need to ask a complaint form apaah weakness experienced after the move, morning, noon or night. In addition also ask double vision speech problems, swallowing or breathing.On physical examination check for lack of the muscle. Moreover check also eye movements, breathing and speech patients. Try asking the patient to count to 100. Note whether the patient's voice weakened.Diagnosis can be aided by having the patient perform repetitive activities arise until signs of exhaustion. For certainty of diagnosis, it is necessary diagnostic tests as follows:1. Anti-acetylcholine receptor antibodiesThese antibodies specific for myasthenia gravis, thus very useful for diagnosis. Antibody titer was elevated in 90% of patients with myasthenia gravis groups IIA and IIB, and 70% of patients with class I. This antibody titers usually correlate with disease severity.
2. Anti-skeletal muscle antibody (anti-striated muscle antibodies)These antibodies are found in over 90% of patients with thymoma and approximately 30% of patients with myasthenia gravis. Patients are no antibodies in the serum and also no anti-acetylcholine receptor antibodies, the possibility of thymoma is very small.
3. Test tensilon (edrofonium chloride)Tensilon is a cholinesterase inhibitor. This test is very useful when checking anti-acetylcholine receptor antibodies can not be done, or negative interim results of a clinical examination is still suspected of myasthenia gravis.If no side effects after the test 1-2 mg intravenously, then again 5-8 mg injected tensilon. The reaction is considered positive if there was a clear improvement in muscle strength (eg, 1 minute), the disappearance of ptosis, arm abduction can be maintained in the position longer, and increased vital capacity. This reaction will not last longer than 5 minutes. If a positive result is obtained, the diagnosis needs to be made between myasthenia gravis syndrome miastenik true.Miastenik syndrome has symptoms similar to myasthenia gravis, but the cause was related to pathological processes such as diabetes, thyroid disorders, and malignancies that have spread. Age incidence of both diseases is an important differentiator. Patients with myasthenia true usually young, while miastenik syndrome usually older. Miastenik syndrome symptoms usually disappear when the underlying pathology of successful diatasi.Tes can be combined with EMG examination.
4. Thorax X-raysPhotos chest in the antero-posterior position and lateral needs to be done, to see if there thymoma. If you need to do a scan of tomografik examination.
5. Test WartenbergIf these symptoms are not clear on the eyelids, can be tried Wartenberg test. Ask the patient to stare without blinking an object located over areas of both eyes some time. In myasthenia gravis affected eyelid ptosis show.
6. Test prostigminProstigmin 0.5 to 1.0 mg mixed with 0.1 mg of atropine, sulfas injected intramuscularly or subcutaneously. The test is considered positive if the symptoms disappear and energy improved.

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